TITLE: GCN CIRCULAR NUMBER: 34834 SUBJECT: GRB 231017A: LCOGT Optical Upper Limits DATE: 23/10/18 20:47:26 GMT FROM: Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu> R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the Fermi GRB 231017A field (Fermi GBM team, GCN 34822) with the LCOGT 1-meter Sinistro instrument at the Teide Observatory, Tenerife site, on October 18, from 01:01 to 01:34 UT (corresponding to 15.93 to 16.48 hours from the GRB trigger time) with the SDSS r and i filters. We performed a series of 3x300s exposures in each band. We do not detect a source within the Swift-XRT error region around the candidate X-ray source (Dichiara et al., GCN 34829) in either band. The following upper limits are calculated using the PanSTARRS catalog as reference: r > 23.0 i > 22.6 These magnitudes are not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/34834. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...